Retrospective method
Collapsed as-built, or but-for analysis
Take the as-built programme, remove the delay events, and see when the works would have finished without them.
- Jurisdiction
- General method guidance, not jurisdiction specific
- Law and editions as at
- 3 August 2026
- Last reviewed
- 3 August 2026
- Editorial status
- Editorial draft, not yet independently reviewed
The question it answers
What would have happened but for these events?
Retrospective counterfactual testing where a validated as-built programme with defensible logic exists.
Minimum evidence
- A validated as-built programme
- Defensible logic applied to as-built activities
- Evidence supporting each event removal
An as-built programme is a record of what happened, and records do not contain logic. Every relationship in a collapsed as-built was placed there by somebody, which means every relationship is contestable and every one must be visible.
Where the method is used, run and disclose the alternatives. An analysis that survives three reasonable logic sets is evidence. One that only works under a single undisclosed set is not.
Strengths
- Directly answers the counterfactual question a tribunal often asks
- Intuitive to explain: this is what would have happened without the event
Frequent failures
- Logic invented for an as-built record that never had any
- Circular removals, where the event is removed along with its own consequences
- Pacing and mitigation ignored, so the counterfactual is fictional
Mandatory caution
Notoriously sensitive to the logic the analyst inserts. Expose every logic edit and run sensitivity cases, or the result is an artefact of undisclosed choices.
Other methods
Where the record comes in
Every mechanism on this page turns on evidence: what happened, what was known and when. A record built as the job happens is worth more than any argument assembled afterwards. Construction Metric keeps that record automatically, from the messages, photographs and voice notes a site team already sends.
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The analysis on this site is only as fast as the evidence behind it. AI Metric builds bespoke systems for consultancies, contractors and claims teams: document and correspondence triage, event registers assembled from the project record, programme and cost reconciliation, and drafting support that always cites the document it came from. Built for review by your own experts, never to replace their judgement.
Do not overread this page
No method decides entitlement, and no method is court approved. A method is fit when it answers the relevant question with the reliable data available, respects the contract and the governing law, and survives alternative explanations. The choice must be explained and defended, not asserted.
General explanation of how contract mechanisms, analysis methods and legal principles generally work. It is not legal or contractual advice, not an opinion on any project, and no standard-form contract wording is reproduced anywhere on this site. Standard forms are routinely amended, so every default described here, including every time period, can be different on your project. Your executed contract, as amended, and the governing law and forum always control. Deadlines may already be running: if an event has occurred, preserve your position and take qualified advice.